The present invention relates generally to a coupling for joining two external surfaces and more specifically to an improved latching coupling for two exterior surfaces.
In the building industry, the use of prefabricated elements to form walls, columns and other structural and non-structural members has steadily increased. In some situations, it is very desirable aesthetically to join prefabricated elements into a resulting unit with blind or hidden seams. This would give the impression that the prefabricated unit was not prefabricated and was formed as a single unitary or integral member.
One form of locking joint used in the prior art to interconnect a pair of prefabricated panels includes a tongue-in-groove, as illustrated in U.S. Pat. No. 2,430,200. Because the insertion is at an angle relative to the resulting longitudinal axis of the tongue-in-groove member, the elements must be rolled or rotated during insertion to form a flush or planar structure. This roll action produces an exposed seam at the junction. Also, there is no locking device to prevent the unrolling except possibly loading force in the installed condition. Without a locking device, the structure is not stable.
The use of locking devices integral with or separate from the interlocking members is illustrated in U.S. Pat. Nos. 3,111,205 and 3,411,261. These additionally are roll-type entries and therefore, have the same problem of exposing the mating seam. Similarly, the latches are designed to prevent unrolling only and are not designed to add structural stresses to provide a stable self supportive structure. In each of these patents a framing member is necessary about the interlocked elements.
The use of non-roll interlocking structural elements is illustrated in U.S. Pat. No. 3,055,461. Because the complementary male and female surfaces all meet simultaneously, any error in insertion or manufacturing tolerances prevents a resulting totally flat surface, as well as a totally blind or hidden seam. Spot welding or riveting is required to maintain the elements together.
Because the prior systems of interlocking panels or elements did not provide a rigid interlocking structure, the diameter of columns which were rigid or static was limited. The more parts needed, the stability and rigidity of the column decreased, and therefore required external clamping devices or rings. This made it difficult to assemble and work with at the construction site.
Thus, it is an object of the present invention to provide a new interlock joint coupling for interlocking elements which provides a blind seam.
Another object of the Present invention is to provide an interlocking joint coupling which is not process tolerance dependent in order to produce a blind seam.
A still even further object of the present invention is to provide an interlocking joint coupling wherein the latch is self-locking.
A still even further object of the present invention is to provide an interlocking joining coupling for elements or panels which sets up structural forces to assure the stability of the resulting product.
A still even further object of the present invention is to provide a interlocking coupling system for elements which interlock together to provide a free-standing stable column of any diameter.
These and other objects are attained by providing a coupling which has a male and female member having complementary latching portions, all of which are dimensioned and positioned so as to assure that a first surface, which extends from the edge at which the two exterior surfaces are to meet, engage in their mating position before second surfaces which extend from the first surfaces at an angle during the insertion along the longitudinal axis of the male and female member. The complementary latching portions apply continuous mating forces to the first and second surfaces, which form complementary shoulders, when mated. The length of the female member from its shoulder to a base of its recess is greater than the length of the male member from its shoulder to a distal end to prevent contact between the base and the distal end when mated. Also, the width of the male is smaller than a corresponding distance across the recess of the female member when mated to also allow proper mating of the male and female first and second surfaces.
The first surface of the male and female members extend at an angle less than 90.degree. with respect to the longitudinal axis of the recess. The angle that the first surfaces make with the longitudinal axis of the recess are different such that the first surfaces diverge from the edge when mated. A portion of the male and female members which extend from the second surface extend from the second surface at an angle and immediately adjacent thereto are shaped so as not to engage prior to the complementary first and second surfaces during mating. The portions of the male and female member extending from the second surface do not engage when mated. The angle formed by the complementary shoulders permit the first surface to engage prior to the second surface during mating.
The latching portions are displaced from the longitudinal axis of the male and female members to allow insertion along the longitudinal axis. The recess of the female member is generally U-shaped with a first end extending from its shoulder and a second end on which the latching element of the female member is positioned. The female latching member includes a protruberance extending into the recess traverse to the recess longitudinal axis and rides along a camming surface of the male member and latches at a latch surface which is at a non-orthogonal angle with respect to longitudinal axis. This non-orthogonal latching surface of the male member allows the latch to provide the continuous mating forces to the first and second surface of the complementary shoulders when the male and female members are mated.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.